Elektrospin yöntemiyle termoelektrik nano yapılar üretimi ve karakterizasyonu
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Dosyalar
Tarih
2013-12-04
Yazarlar
Dergi Başlığı
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Yayıncı
Selçuk Üniversitesi Fen Bilimleri Enstitüsü
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Bu çalışmada, oksit termoelektrik madde olarak bilinen sodyum kobaltit ( NaxCo2O4 ) ve onun nikel ve bor katkılı türevleri elektro-eğirme metoduyla üretilerek, termoelektrik ve diğer fiziksel özellikleri incelenmiştir. Bu amaçla 5 farklı polimer çözelti hazırlanmış olup bu çözeltilerden 4 tanesi elektro-eğirme yöntemi ile nanolif haline dönüştürülmüştür. Diğer örnek ise polimerik sol-jel metodu ile üretilmiştir. Her iki yöntemle üretilen numuneler kalsinasyon işlemine tabi tutularak toz halinde termoelektrik nanokompozit seramik malzemeler elde edilmiştir. Nanoliflerin kalsinasyon işlemi öncesi ve sonrasındaki morfolojileri taramalı elektron mikroskobu ile incelenmiştir. Numunelerin yapısal analizi XRD ve kızıl ötesi spektroskopisi (FTIR) ile karakterize edilmiştir. Aynı zamanda elektro-eğirme yöntemi ile üretilen numunelerin termal özellikleri, DSC, TGA ve DTA ölçümleri ile belirlenmiştir. Daha sonra, toz halindeki malzemeler soğuk pres yöntemiyle pelet haline getirilmiş ve uygun sıcaklıkta sinterleme işlemine tabi tutulmuştur. Sinterleme sonrası bütün numunelerin termoelektrik özellikleri (Seebeck katsayısı, elektriksel iletkenlik, ısıl iletkenlik, termoelektrik kalite faktörü) 10-300 K sıcaklıkları arasında Lot ? Oriel PPMS sistemi ile ölçülmüştür. Sonuç olarak, üretim yönteminin ve Ni, B ilavesinin sodyum kobaltitin termoelektrik özellikleri üzerindeki etkileri ayrıntılı olarak incelenmiştir.
In this study, the physical and thermal properties of sodium cobaltate (NaxCo2O4), known as the oxide thermoelectric material, and its nickel and boron doped derivatives produced by electrospinning method are investigated. For this purpose, 5 different polymer solutions were prepared. While 4 sample were transformed into nanofiber form by electrospinning technique another example was produced by the method of polymeric sol-gel. All of the samples were performed to calcination process and thermoelectric nanocomposite ceramic materials were obtained in powder form. Nanofibers morphology were examined by scanning electron microscopy before and after the calcination process. Structural analysis of the samples were characterized by XRD apparatus and infrared spectrometry (FTIR). Also the thermal properties of the samples produced by the method of electro-spinning were determined by the DSC, TGA and DTA measurements. Then the pulverulent materials were pelleted with cold press and sintered under proper temperature. The thermoelectric properties (Seebeck coefficient, electrical conductivity, thermal conductivity, figure of merit ) of the samples were measured by Lot - Oriel PPMS system at temperatures between 10-300 K after sintering. As a result, the production method and the effects of Ni, B on the thermoelectric properties of sodium cobaltate were investigated in detail.
In this study, the physical and thermal properties of sodium cobaltate (NaxCo2O4), known as the oxide thermoelectric material, and its nickel and boron doped derivatives produced by electrospinning method are investigated. For this purpose, 5 different polymer solutions were prepared. While 4 sample were transformed into nanofiber form by electrospinning technique another example was produced by the method of polymeric sol-gel. All of the samples were performed to calcination process and thermoelectric nanocomposite ceramic materials were obtained in powder form. Nanofibers morphology were examined by scanning electron microscopy before and after the calcination process. Structural analysis of the samples were characterized by XRD apparatus and infrared spectrometry (FTIR). Also the thermal properties of the samples produced by the method of electro-spinning were determined by the DSC, TGA and DTA measurements. Then the pulverulent materials were pelleted with cold press and sintered under proper temperature. The thermoelectric properties (Seebeck coefficient, electrical conductivity, thermal conductivity, figure of merit ) of the samples were measured by Lot - Oriel PPMS system at temperatures between 10-300 K after sintering. As a result, the production method and the effects of Ni, B on the thermoelectric properties of sodium cobaltate were investigated in detail.
Açıklama
Anahtar Kelimeler
Elektro-eğirme, Nano-seramik, Oksit termoelektrik materyaller, Sodyum kobaltit, Sol-jel, Termoelektrik, Elektrospinnig, Nanoceramic, Oxide thermoelectric materials, Sodium cobaltate, Solgel, Thermoelectric
Kaynak
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Sayı
Künye
Erdal, M. O. (2013). Elektrospin yöntemiyle termoelektrik nano yapılar üretimi ve karakterizasyonu. Selçuk Üniversitesi, Yayımlanmış doktora tezi, Konya.
